<p>So… I am taking the AB class, but taking the BC test. I’ve been self studying the BC topics. Polar and Parametrics are down. I still have a bit of trouble with series. For my final in the class, it was a released AB test; I got an easy 5 on it while getting 100% on the FRQ… Took the BC released test on Saturday; I got an equivalent of a 3… So, I kind of regret signing up for BC…</p>
<p>So for the 1998 BC test, Part B # 90</p>
<p><a href=“http://staff.4j.lane.edu/~windom/AP/ap%20multiple%20choice.pdf[/url]”>http://staff.4j.lane.edu/~windom/AP/ap%20multiple%20choice.pdf</a></p>
<p>How is the answer A? The starting position is (2,0), not (0,2)!</p>
<p>@davidthefat: That’s what I did too, and the worst part is that I’m not signed up for any tutoring programs. All of my friends in AB right now are in an after school program called Treehouse… Ugh.</p>
<p>@Mascara: Look carefully at the axis. The given graphs are s(t). The horizontal axis is time; the vertical is distance.</p>
<h1>90 is tricky.</h1>
<p>Suppose the acceleration is a=2. It is positive so it fits the description in the problem.
Then, velocity:</p>
<p>v(t)= 2t+C
==> since the particle starts from rest, C=0.</p>
<p>Position, is then:</p>
<p>p(t)= t^2+C</p>
<p>Now, given that (2,0) is a point on a curve,
0=2^2+C
C=-4</p>
<p>And your position is p(t)=t^2-4</p>
<p>I know, there is no graph that goes through (0,4). But that is not important, really. The only thing that is important is the fact that the position curve is centered on the y-axis. That is, the vertex of the parabola is always going to be at some point (0,a). Why? Your velocity is always going to be v(t)=a*t, which means that your position is always going to be of the form ax^2/2 + C, with a vertex centered on the y-axis. Option c is not centered on the y-axis, hence it is wrong.</p>
<p>Hope that makes some sense.</p>
<p>Anyone know which trig identities we should know? Did both practice tests in PR, but they had a good number of problems involving trig identies beyond the (sinx)^2 +(cosx)^2=1</p>
<p>Since the particle starts at the point (2,0), it is at a DISTANCE of 2 from the origin at t=0. We want the graph of s(t), where s is the distance, so s(0)=2. A is the correct graph.</p>
<p>@ForeverAlone:</p>
<p>The only trig identities I found necessary are these:</p>
<p>cos(x)^2+sin(x)^2=1
cos(x)^2= [1+cos(2x)]/2
sin(x)^2= [1-cos(2x)]/2
sin(2x) = 2sin(x)cos(x)</p>
<p>Obviously the more you know the better, but I think those are the essential ones for the test.</p>
<p>Those all can be derived from that one formula.</p>
<p>@davidthefat:</p>
<p>That may be true, but like anything, if you know it by heart than it is easier to use during the test. I mean I could derive all of the derivative formulas by the limit process, but I find memorization of essential functions way easier.</p>
<p>I personally just find it easier to just remember the one formula and not stress out about the rest. There are only a handful calculus rules; just learn the intuition behind them.</p>
<p>For trig integrals, you only need to know the Pythagorean identity and the power reducing identities. It would be ideal to know more, but the rest are rarely if ever tested.
You should know logarithm rules too, the simple ones like log(A)+log(B)=log(AB) and Alog(b)=log(b^a) because collegeboard likes to screw you up with logs.</p>
<p>Anyone else feel the the princeton Review Calc BC practice are slightly hard, but the FRQ are easy?</p>
<p>I agree with Enmity. Goodness knows how many times I couldn’t remember that log 10 - log 5 = log (10/5)</p>
<p>Blehhh D:</p>
<p>One day left. I wish I had studied earlier. Oh well. 
Starting to get comfortable with the practice problems</p>
<p>I recently took the diag on sparknotes and got a 3, but got a 5 on the diag my teacher gave to me. Is the one on Sparknotes a lot harder?</p>
<p>^ What was the diagnostic test your teacher gave you? If it was a college board one, chances are that one mirrors your actual capability a bit better.</p>
<p>The sparknotes one was a little harder for me as well, mostly because the questions were not written on paper but on a computer screen. Harder to solve problems when they’re not written down (for me at least). The diagnostic test that my teacher gave was significantly easier, in my opinion because they did not actually require math but focused a lot on concepts instead. The sparknotes one was mainly computational like “the integral of x^2*e^-x dx from 0 to infinity”. Solving those problems on multiple choice tends to be a little difficult because they take longer to solve. Generally, you should trust the collegeboard test more than the sparknotes one.</p>
<p>@Mascara Yeah, and don’t forget Laws of Exponments. CB will expect us to know how to take care of separable equations involving integral of dy/y.</p>
<p>And as for logs, remember that -log (x) = log (x^-1) = log (1/x)</p>
<p>is it just me, or does the sparknotes diagnostic test take WAY longer than usual CB tests?</p>
<p>Does anyone know where to get that calculator program that has a better display format than the fault of TI-84+ and up? For example e^x appears superscripted like
<a href=“http://upload.wikimedia.org/wikipedia/en/math/1/a/9/1a980c420b5c546f90ebe42619b7d848.png[/url]”>http://upload.wikimedia.org/wikipedia/en/math/1/a/9/1a980c420b5c546f90ebe42619b7d848.png</a></p>
![http://upload.wikimedia.org/wikipedia/en/math/1/a/9/1a980c420b5c546f90ebe42619b7d848.png[/url]](http://upload.wikimedia.org/wikipedia/en/math/1/a/9/1a980c420b5c546f90ebe42619b7d848.png%5B/url%5D){kind=link}
<p>on the calculator and the actually integral symbol shows instead of fnInt</p>
<p>This site shows you how to get mathprint(which I believe is what you’re referring to):
[Godly</a> Dominion: MathPrint on the TI-84](<a href=“http://bird-godlydominion.blogspot.com/2010/02/mathprint-on-ti-84_15.html]Godly”>Godly Dominion: MathPrint on the TI-84)</p>